virtual groups may die, if (a) the framework is reinforced in such a way as to prevent an effective invasion, or (b) the invasion takes place but the group created dies (mochikomi).

If a framework is turned into territory, that means all the virtual groups inside it are now dead. Often the final play consolidating the territory is very efficient; the translation of that in virtual group terms may be that it kills two virtual groups at once.

Iron pillar

For example Black plays 1 (the iron pillar) in the hope of reducing to nothing White's aji to live around a, and around b.

The terminology of virtual groups is just a way of discussing aji for life. It is quite graphic and suggestive. I learned it in seminars of Matthew Macfadyen. Charles Matthews

When I looked at the title I thought virtual groups are random black and white groups spontaneously appearing out of the blank go board and then annihilating again, like virtual particles and antiparticles appearing and disappearing in space.

virtual groups last edited by 98.206.23.16 on February 4, 2011 - 23:14